Computing power is reaching a crisis point. If we continue to follow the trend that has been in place since computers were introduced, by 2040 we will not have the capability to power all of the machines around the globe.

Now a new study published in Elsevier’s Physics Reports shows ultra-thin layers of materials could provide the answer to this crisis, by forming the basis for a quantum computing chip.

Moore’s law predicts that the density of transistors on silicon chips will double approximately every 18 months. But this law is starting to reach its natural limit.

So, researchers are turning to quantum computing. Quantum bits, or qubits, which can be on and off at the same time, provide a revolutionary high-performance system in which information is stored and processed more efficiently.

One of the biggest difficulties in progressing with quantum computing is finding the best materials to use in chips. When graphene was discovered in 2004, researchers thought it might hold the answer. The Nobel Prize awarded for the discovery of graphene in 2010 highlighted the promise of this material, but so far, at least, it has not led to wide-scale quantum computing.

Previous experiments have used graphene placed on a substrate of silicon dioxide. Now researchers are turning to other, similar materials, to study how effective they might be in quantum chips. In the paper, researchers led by Kuei-Lin Chiu from the Massachusetts Institute of Technology and Yang Xu from Zhejiang University in China have looked into a special type of substrate: layered materials. “We are investigating whether layered materials can be used to store bits of information for the next-generation switching technologies beyond Moore’s law,” Chiu says.

They looked into what kind of materials would be the best basis for use in quantum computing. “Graphene single electron transistors, or quantum dots, have been widely studied in the past ten years. In our paper, we review the more recent studies where graphene dots were placed on [one of the layered materials] to reduce the substrate's disorder and compare them to the earlier studies.”

They examined a variety of materials. “The interesting thing about this research is how we choose the right material, find out its unique properties and use its advantage to build a suitable qubit,” adds Chiu. The researchers also say several layered materials could be combined with a superconductor to make a special type of qubit called a topological qubit or Majorana qubit.

Chiu says that advances in this research over recent years are getting us closer to quantum computing. “Although there are still obstacles to overcome, it would be both disappointing and surprising if these qubits, now ardently sought, do not materialise.”


Article details

Chiu, K-L and Xu, Y.: "Single-electron transport in graphene-like nanostructures", Physics Reports (2017)